How to use the Energy Harvesting LCD Display in the ST25DV Discovery kit with a custom ST25DV board

[VColi.1]

I want to use the LCD Display in the ST25DV Discovery kit "MB1283" Motherboard to measure the harvested energy(Voltage and Current) from my custom ST25DV04K board with Antenna.

I know how to select the Energy Harvesting display (with the Micro USB connected to external power) to display harvested energy with the ST25DV_Discovery_Ant provided in the kit, but what pins on the J4 "ST25DX" 14-pin Extension Connector (or elsewhere on MB1283 motherbard) do I need to connect from my custom board to measure / display Energy Harvest?

[Dave D]

Hi,

If you have a look on the schematic of the antenna board provided with the kit, you can see that the Energy Harvesting pin is on the pin 2 of the 14 pin connector.

https://www.st.com/resource/en/schematic_pack/st25dv-ant-c5-schematics.pdf

You can connect you own board with this pin connected. On the motherboard side, it is the pin 2 names "EH".

Regards

[VColi.1]

Dave,

Thank you!  Connecting the tag’s harvesting “Vout” to pin 2 (the Energy Harvesting pin) on motherboard’s 14 pin connector and the tag’s Ground to pin 3 on the 14 pin connector works!

Two questions:

1. To get to the Energy Harvesting function, I must first power-power up the motherboard with the ST25DV_Discovery_ANT_C5 connected and select the Energy Harvested function, otherwise I get “ST25DV I2C Error”.  Is it possible to remove this step (i.e., boot directly to Energy Harvesting?)
2. Is a “ST2DV Demonstration” firmware update available for the kit?  I am running Version 1.0.5.

Vince

[Rene Lenerve · Accepted solution]

Hi VColi.1,

If you want to bypass the Tag detection at demo boot you will have to comment some code and rebuild the firmware.

Commenting these lines in the main.c should do the trick :

  if( ST25DV_pwm == 0 )
  {
    ST25_RETRY(BSP_NFCTAG_Init(BSP_NFCTAG_INSTANCE));
  }
  else
  {
    ST25DV_Scope_Start( );
  }

and these lines in Menu_definition.c:

  ST25_RETRY( BSP_NFCTAG_ReadUID(BSP_NFCTAG_INSTANCE, &uid) );
  ProductRef = (uid.MsbUid & 0xFF00) >> 8;
  if( ST25DV_AM_I_OPEN_DRAIN(ProductRef))
  {
    /* GPO Open drain => 8 pins package, so remove the LPD demo */
    memcpy(&ST25DVStatesMenuItems[2],&ST25DVStatesMenuItems[3],sizeof(struct sMenuItem));
    ST25DVStatesMenu.nItems--;
  }

and last ones in st25dv_features_demo.c (function EnergyHarvesting line 191 and 255);

...
ST25_RETRY(BSP_NFCTAG_SetEHENMode_Dyn(BSP_NFCTAG_INSTANCE));
...
ST25_RETRY(BSP_NFCTAG_ResetEHENMode_Dyn(BSP_NFCTAG_INSTANCE));
...

Another way to proceed (modifying the hardware only), is to keep the daughter board connected.

Remove R4 to disconnect EH from daughter board's tag:

And link your tag's EH pin to the EH pin on the daugther board (ST1-3 or ST3-2)

Doing this should allow you to start the demo without the error message and measure the EH from your other tag.

Last point you can find an update of the firmware 1.2.0 in the following link:

https://www.st.com/en/embedded-software/stsw-st25dv001.html 

I hope this can help you.

Kind Regards.